The fructose 2,6-bisphosphatase activity of cytosolic phosphofructokinase 2/fructose-2,6-bisphosphatase catalyzes the hydrolysis of fructose 2,6 bisphosphate to form fructose 6-phosphate. Fructose 2,6 bisphosphate is a key allosteric regulator of PFK1. In its absence the activity of PFK1 is reduced while fructose 1,6-bisphosphatase is activated, thus inhibiting glycolysis and favoring gluconeogenesis (Pilkis et al. 1995).